Xu Zhenguang knocks the "school bell" at the primary school of Siliu Village in Rongshui County, southwest China's Guangxi Zhuang Autonomous Region, Jan. 12, 2009. Only 3 pupils were still attending the school while others left with their migrant-worker parents in recent years. Mr. Xu, who has been a teacher for 37 years, stuck to his job at the four-person school.